The present invention relates to a device for lever operation to regulate the heating and air conditioning of automobiles and in particular to a multi-control mechanism operated by means of a single lever on the dash.
Remote control arrangements with single-lever operation are known which activate successively several heating system components by means of cables.
Involved in general are mechanical controls realized by means of the main lever, the movement of which is transformed by a set of slots or grooves acting as cams in which are guided projecting pins. Cams and pins are borne alternatively by the main lever, by intermediate articulated links or directly by a supporting plate of the mechanism.
More precisely, a known device consists of a supporting plate provided with two fixed pins about each of which a single lever pierced by two curvilinear openings, articulates successively while the other pin slides in its associated slot.
This arrangement, more especially adapted to the symmetric control of two cables hooked to the lever, does not permit obtaining a constant actuating torque in the case of unbalance in the forces required by each of the cables or, again, when it is necessary to control more than two cables.
On the other hand, the geometry of the plate-lever assembly and the configuration of the slots or cams determine in a fixed manner the trajectory of each point of the lever and thus the orientation of the take-off of the cables, which it is practically impossible to modify for adaptation to different types of vehicles.
Another drawback resides in the fact that the guide slots generate friction which makes it harder to manipulate the lever and entails the risk of jamming, especially in the case of low-cost mass production with large tolerances.